MacPherson claims he was having a discussion at half time with the referee when the linesman barged in to add his tuppence worth - despite the fact he wasn't being talked to. He later criticised the linesman's attitude, and the SFA have now asked him to explain his comments.
It seems a bit bizarre this is happening considering it was only the linesman's attitude that was criticised, not his decision making (although he effectively did that as well). A touch line ban or fine could be in the offing.
Nice to know we live in a society where free speech is allowed!